The Bridget Jones's Diary star admits her directorial debut was never planned, and she had initially envisaged producing and starring in the script by writer Anthony Tambakis.
But after the project failed to draw investors and directors to the movie, Zellweger decided to step up to the role, and she is delighted with the project's progress.
She tells The Hollywood Reporter, ""Anthony sent the script to me last year, asking thoughts and whether I'd partner with him to produce it. I'm such a fan of his writing... he has an ability to capture worlds with remarkable compassion, humour and intimacy and the truth of his characters' humanity is felt in every line.
""I asked him if he'd consider my producing and playing PJ. By the new year, the effort to get the film financed had fizzled. I couldn't get the script out of my head, but we didn't have a director and weren't making any headway.
""During a work session for (new TV drama) Cinnamon Girl in early 2012, I brought up 4 1/2 Minutes again, Anthony suggested I direct, and it all started rolling from there.""